The AN/ALQ-144, AN/ALQ-147, and AN/ALQ-157 are US infra-red guided missile countermeasure devices (

IRCM An infrared countermeasure (IRCM) is a device designed to protect aircraft from infrared homing ("heat seeking") missiles by confusing the missiles' infrared guidance system so that they miss their target ( electronic countermeasure). Heat-se ...

). They were developed by Sanders Associates in the 1970s to counter the threat of

infra-red Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...

guided surface to air missiles like the

9K32 Strela-2 The 9K32 Strela-2 (russian: Cтрела, "arrow"; NATO reporting name SA-7 Grail) is a light-weight, shoulder-fired, surface-to-air missile (or MANPADS) system. It is designed to target aircraft at low altitudes with passive infrared homing guid ...

. While decoy flares were effective at jamming first generation infra-red

guided missile In military terminology, a missile is a guided airborne ranged weapon capable of self-propelled flight usually by a jet engine or rocket motor. Missiles are thus also called guided missiles or guided rockets (when a previously unguided rocket ...

s, each flare was only effective for a short period. If an aircraft needed to loiter over a high risk area or was flying slowly (as helicopters do), it would require a large number of flares to decoy any missile fired at it. The IRCM provided constant protection against infra-red guided missiles. The ALQ-144 and ALQ-147 were first delivered to the

US military The United States Armed Forces are the Military, military forces of the United States. The armed forces consists of six Military branch, service branches: the United States Army, Army, United States Marine Corps, Marine Corps, United States N ...

in 1981. Currently there are over 3,500 in use with the US military, and a total of 6,000 in use by nineteen countries globally. Seven hundred ALQ-157 systems are currently in service.

ALQ-144/ALQ-147

Both systems consist of a heated

silicon carbide Silicon carbide (SiC), also known as carborundum (), is a hard chemical compound containing silicon and carbon. A semiconductor, it occurs in nature as the extremely rare mineral moissanite, but has been mass-produced as a powder and crystal s ...

block that radiates a large amount of infra-red energy. It is surrounded by a large cylindrical mechanical shutter that modulates the infra-red output, producing a pulsing pattern. Early infrared guided missiles used a rotating

reticle A reticle, or reticule also known as a graticule, is a pattern of fine lines or markings built into the eyepiece of an optical device such as a telescopic sight, spotting scope, theodolite, optical microscope or the screen of an oscilloscop ...

. When a target was not on the sensor's centerline, it would produce a pulse as the reticle swept over the target. When the target was on the sensor's centerline, the sensor would produce a constant signal. This constant signal was required by the early missiles to produce a "lock on" that would allow a launch. The ALQ-144 and 147 IRCM produced a pattern of pulses that was approximately synchronized with the rotation rate of these reticles. Before launch this would prevent the missile actually locking onto the target, preventing the operator from firing the missile. After launch this would cause the missile to think that the target was off to one side and cause the missile to steer away from the aircraft carrying the IRCM. The introduction of rosette and "staring" scanning techniques in second generation missiles reduced the effectiveness of the ALQ-144 and 147; later upgrades restored the effectiveness of the jammers. The ALQ-144A was rushed into US service in time for the

1991 Gulf War The Gulf War was a 1990–1991 armed campaign waged by a 35-country military coalition in response to the Iraqi invasion of Kuwait. Spearheaded by the United States, the coalition's efforts against Iraq were carried out in two key phases ...

, as Iraq had stocks of 9K34 Strela-3 and 9K38 missiles, against which the ALQ-144 was only partially effective. By the time the war started, two-thirds of the

AH-64 Apache The Boeing AH-64 Apache () is an American twin- turboshaft attack helicopter with a tailwheel-type landing gear arrangement and a tandem cockpit for a crew of two. It features a nose-mounted sensor suite for target acquisition and night v ...

s in the persian Gulf had been upgraded to ALQ-144A standard. The only AH-64 Apache lost to an infra-red guided missile was hit by a 9K34 Strela-3 missile; the helicopter in question was one of the few that had not been upgraded. The ALQ-144's distinctive appearance has earned it the nicknames "disco light", "disco ball", or "mirror-ball".

ALQ-157

Produced by

Loral Loral may refer to: * Loral Corporation, contractor founded in 1948 in New York by William Lorenz and Leon Alpert as Loral Electronics Corporation * Loral Space & Communications, satellite communications company * Loral GZ-22, a non-rigid airship * ...

, the system consists of two emitters, each one covering one side of a large aircraft. The system is microprocessor controlled and has five pre-set jamming patterns.

Specifications

Variants

* ALQ-144 electrically powered IRCM ** ALQ-144A upgraded system to deal with more recent generations of IR guided missiles. **ALQ-144A(V)1 – Standard in helicopter jammer **ALQ-144A(V)3 – Added RFCM on/off switch **ALQ-144A(V)5 – Increased protection with a dual phaselocked transmitters and jam code selector switch on the operator control unit **ALQ-144A+ – Increased protection with the higher power **ALQ-144A+(5) – Increased protection plus with the dual phaselocked ALQ-144A+ transmitter * ALQ-147 mounted in a modified 150 US gallon (570 liter)

drop tank In aviation, a drop tank (external tank, wing tank or belly tank) is used to describe auxiliary fuel tanks externally carried by aircraft. A drop tank is expendable and often capable of being jettisoned. External tanks are commonplace on modern ...

, it is a fuel powered IRCM. ** ALQ-147A upgraded system to deal with more recent generations of IR guided missiles. * ALQ-157 large aircraft version of the system fitted to

CH-47 Chinook The Boeing CH-47 Chinook is a tandem rotor helicopter developed by American rotorcraft company Vertol and manufactured by Boeing Vertol. The Chinook is a heavy-lift helicopter that is among the heaviest lifting Western helicopters. Its name, C ...

and

C-130 Hercules The Lockheed C-130 Hercules is an American four-engine turboprop military transport aircraft designed and built by Lockheed (now Lockheed Martin). Capable of using unprepared runways for takeoffs and landings, the C-130 was originally desi ...

aircraft, consists of two units, each giving semi-circular coverage. ** ALQ-157M upgraded system to deal with more recent generations of IR guided missiles.

References

* ''War in the Fourth Dimension'', Dr Alfred Price, * ''The Naval Institute Guide to World Naval Weapon Systems'', Norman Friedman, {{DEFAULTSORT:AN ALQ-144 Missile countermeasures Military electronics of the United States Equipment of the United States Air Force Electronic warfare equipment Military equipment introduced in the 1980s

ALQ-144/ALQ-147

ALQ-157

Specifications

Variants

See also

Related ECMs

References